1. Field of the Invention
The present invention relates to a vehicular power transmission control apparatus, especially to a vehicular power transmission control apparatus applied to a vehicle comprising an internal combustion engine and an electric motor as power sources.
2. Description of the Related Art
In these days, a so-called hybrid vehicle comprising an internal combustion engine and an electric motor (electric motor generator) as power sources has been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 2000-224710). In the hybrid vehicle, the electric motor is used as the power source generating a driving torque for driving the vehicle together with the internal combustion engine or by itself, or is used as a power source for starting the internal combustion engine.
Further, the electric motor is used as an electric motor generator for generating a regeneration torque to provide a breaking force to the vehicle, or is used as an electric motor generator for generating an electric power which is supplied to and stored in a battery of the vehicle. These usages of the electric motor can improve a total energy efficiency (fuel consumption) of the vehicle as a whole.
Generally, in the hybrid vehicle, a torque of an output shaft of the internal combustion engine and a torque of an output shaft of the electric motor are controlled in such a manner that a sum of an internal-combustion-engine-side-output-torque and an electric-motor-side-output-torque becomes equal to (coincides with) a required driving torque. The internal-combustion-engine-side-output-torque is a torque which is transmitted to the output shaft of the transmission and which is based on (owing to) a torque of the output shaft of the internal combustion engine. The electric-motor-side-output-torque is a torque which is transmitted to the output shaft of the transmission and which is based on (owing to) a torque of the output shaft of the electric motor. The required driving torque is a torque based on an operation of the acceleration operating member by a driver of the vehicle.